October 2009

Estimates of Born-Oppenheimer energies of the ground state of the Dihydrogen molecule (H2) previously computed by ITL have enabled a new high precision calculation of the Dihydrogen bond dissociation energy. In a paper recently submitted to the Journal of Chemical Theory and Composition, K. Piszczatowski et al. of Warsaw University, Warsaw, Poland, report a bond dissociation energy that is believed accurate to 9 significant digits, two orders of magnitude better than the best previous experimental result. The X1summation(g+) potential energy curve needed to obtain the new result was derived from computed values of Bohr-Oppenheimer energies published by James Sims of the ITL Mathematical and Computational Sciences Division and Stanley Hagstrom of Indiana University in 2006. When published, those results were the most accurate energy values ever obtained for a molecule of that size, 100 times better than the best previous calculated value or the best previous experimental value.